1. Field of the Invention
The present invention relates to a process for preparing unsaturated aldehydes, unsaturated carboxylic acids and/or conjugated dienes by the reaction of a suitable starting material over a Mo--Sb--Bi--Fe--Ni type catalyst.
2. Description of the Prior Art
Many processes are known for the gas phase catalytic oxidation of propylene or isobutylene to the corresponding unsaturated aldehyde or acid such as those disclosed in U.S. Pat. Nos. 3,454,630; 3,522,299; 3,576,764; 3,778,386; and 3,825,502. On the other hand Japanese application publication No. 32814/73 shows a process for the catalytic oxidation of t-butyl alcohol to methacrolein at selectivities of 58.0 to 84.1 mole % for methacrolein. Further processes are also known for the catalytic oxidation of butenes to 1,3-butadiene such as disclosed in British Patent 1,329,516, and 1,357,848. The disadvantage of these processes is that the selectivity of the conversion of the starting olefin to methacrolein or 1,3-butadiene is insufficient. A need therefore, continues to exist for a catalyst which very effectively promotes the catalytic oxidation of t-butyl alcohol or isobutylene to oxidized products.